How to: Create Transparent Windows Forms
With Microsoft Windows XP, you can control the opacity of windows that are displayed. To make a form more transparent, adjust its Opacity property.
As transparent forms are only supported in Windows 2000 or later, Windows Forms will be completely opaque when run on older operating systems, such as Windows 98, regardless of the value set for the Opacity property.
The dialog boxes and menu commands you see might differ from those described in Help depending on your active settings or edition. To change your settings, choose Import and Export Settings on the Tools menu. For more information, see Customizing Development Settings.
To control the opacity of Windows Forms
In the Properties window, set the Opacity property to a value between 0.0 (complete transparency) and 1.0 (complete opacity).